Early in the film, Donnie Darko wakes up after a night of sleepwalking with the numbers 28:06:42:12 written on his arm.
I know that within the film the numbers refer to Frank telling Donnie:
28 days... 6 hours... 42 minutes... 12 seconds. That... is when the world... will end.
Were these numbers just made up at random by writer/director Richard Kelly, or do they have some hidden meaning?
Taken from the IMDB trivia entry for Donnie Darko:
The movie takes place in 1988. Frank tells Donnie the world will end in 28 days, 06 hours, 42 minutes, and 12 seconds. If you add these numbers, the sum is 88. When Samantha asks when she can have kids, Donnie says: "Not until 8th grade." Donnie mentions to his therapist that his dog Callie died when he was eight. (He is later seen holding a stuffed toy dog in her office.) Donnie jokes about the Back to the Future DeLorean which had a speed of 88 MPH. According to the television reporter, the fire at Jim Cunningham's house was extinguished "sometime after 8:00 last night." The red-eye flight that almost crashes is Flight 2806 which boards at Gate 42 at 12 AM. The climax of Donnie Darko occurs one week before the 1988 US presidential election, when George Bush won on November 8, 1988 11/08/88. The movie was shot (for a budget of less than US$5 million) in 28 days. There are 28 scenes in the director's cut of this film.
Frank says the world will end in "28 days 6 hours 42 minutes 12 seconds." That figure is not random: it comes from adding or subtracting 1 from each part of the figure 27d 7h 43m 11s, which is the precise length of one lunar month (by one of the less-used definitions - sidereal instead of the usual synodic).
Take away from it what you will.
28:06:42:12 comes from the lunar year: 27d 7h 43m 11s = 27:07:43:11 add or subtract 1 from every number.. and u get 28d 06h 42m 12s
